public bool PreFilterMessage(ref Message m)
{
if (m.Msg == WinApi.WM_MOUSEMOVE && autoHideCursor)
{
Point p = new Point(m.LParam.ToInt32());
WinApi.ClientToScreen(m.HWnd, ref p);
if (p != lastMousePoint)
{
lastMousePoint = p;
ShowCursor();
hideCursorTimer.Reset();
}
return(false); // Don't block this message
}
else if (m.Msg == WinApi.WM_MOUSEWHEEL && dispatchMouseWheel)
{
Point p = new Point(m.LParam.ToInt32());
// First, see whether there's an open combobox list popup that must be handled differently
WindowProperties prop = new WindowProperties();
prop.ProcessId = new Window(m.HWnd).ProcessId;
prop.ClassName = "ComboLBox";
prop.Visible = true;
Window popup;
if (Window.TryFind(prop, out popup))
{
// Found a combobox popup window, check coordinates
if (popup.Rectangle.Contains(p))
{
// Mouse cursor is over visible combo listbox popup, let the message pass
return(false);
}
// Mouse cursor is outside the popup, block the message
// (Do not scroll the popup because the mouse is not in it;
// but also do not scroll anything else outside the popup)
return(true);
}
// Regular window surface: find the deepest control below the mouse cursor
Control control = Form.ActiveForm;
while (control != null)
{
Point clientPoint = control.PointToClient(p);
Control subControl = control.GetChildAtPoint(clientPoint, GetChildAtPointSkip.Invisible);
if (subControl == null || subControl is ScrollBar || subControl is ComboBox)
{
break;
}
//System.Diagnostics.Debug.WriteLine("Found control in " + control.Name + " at " + clientPoint + ": " + subControl.Name);
control = subControl;
}
if (control != null)
{
if (control.Handle == m.HWnd)
{
return(false); // The message already arrived for this control, let it pass
}
// Search up the parents for a scrollable panel
Control c = control;
while (!(c is Form))
{
Panel panel = c as Panel;
if (panel != null && panel.AutoScroll)
{
Point scrollPos = panel.AutoScrollPosition;
// Position report is always negative, but new values must be set positive...
scrollPos.X = -scrollPos.X;
scrollPos.Y = -scrollPos.Y;
int delta = m.WParam.ToInt32() >> 16;
delta /= 120; // Convert to number of wheel notches
scrollPos.Y += -delta * 20; // Delta value is "negative" (neg is downwards, pos is upwards)
panel.AutoScrollPosition = scrollPos;
return(true); // Block this message
}
NumericUpDown numericControl = c as NumericUpDown;
if (numericControl != null)
{
decimal value = numericControl.Value;
int delta = m.WParam.ToInt32() >> 16;
delta /= 120; // Convert to number of wheel notches
value += delta * numericControl.Increment;
if (value < numericControl.Minimum)
{
value = numericControl.Minimum;
}
if (value > numericControl.Maximum)
{
value = numericControl.Maximum;
}
numericControl.Value = value;
return(true); // Block this message
}
c = c.Parent;
}
// NOTE: Possible performance improvement: Flag the re-posted message so that we can
// recognise it faster when it re-arrives here and we can let it pass.
// Use either a very high delta value (HIWORD(wParam)) or one of the modifier
// keys MK_* (LOWORD(wParam)) or an unassigned bit of lParam.
//System.Diagnostics.Debug.WriteLine("Re-posting message to " + control.Name);
WinApi.PostMessage(control.Handle, WinApi.WM_MOUSEWHEEL, m.WParam, m.LParam);
// If IMessageModifyAndFilter wasn't System.Windows.Form's internal, we could just
// implement that interface, modify the message and let it pass changed. But so we
// need to block the message and send a new one that we're going to let pass then.
}
return(true); // Block this message
}
return(false); // Don't block this message
}
